Blood serum collection tube and method

ABSTRACT

The disclosure relates to an improved apparatus and an improved method for removing serum from the uppermost portions of a specimen tube of centrifuged blood, in which the blood serum is disposed in a liquid pool above settled-out cellular solid materials. More particularly, the invention is directed to an easily handleable, readily mailable, collection tube closed at both ends by &#39;&#39;&#39;&#39;one shot&#39;&#39;&#39;&#39; valve structures comprising selfsealing elastomeric elements pierced by a special one-piece hollow needle. Additionally, the lower elastomeric element includes an annular piston-like member which is adapted to engage the inner walls of the specimen tube to pump serum therefrom.

United States Patent Brown et al.

BLOOD SERUM COLLECTION TUBE AND METHOD Inventors: Paul Brown; JosephOBrien, both of c/o Metropolitan Pathology Laboratory, Inc., 60 CommerceWay, Ridgewood, NJ. 07606 Filed: Aug. 7, 1972 Appl. No.: 278,227

Related US. Application Data Continuation of Ser. No. 148,872, June 1,1971, abandoned, which is a continuation-in-part of Ser. No. 854,982,Sept. 3, 1969, Pat. No. 3,586,064.

US. Cl 141/1, 23/2585, 23/259, 73/4254, 141/327, 141/330, 210/540,233/26 Int. Cl B01] 11/00 Field of Search 23/2585, 259, 292; 73/4254 R,425.4 P; [28/218 M, 220, 272; l4l/l, 2, 18, 22,113, 250, 3.8, 325, 327,

References Cited UNITED STATES PATENTS 6/1930 Morton 128/220 1 Sept. 24,1974 2,524,363 10/1950 Smith 128/220 2,653,607 9/1953 Deans 128/218 M3,017,883 l/1962 Dickerson, Jr r 128/272 3,481,477 12/1969 Farr 23/2585Primary ExaminerHouston S. Bell, Jr. Attorney, Agent, or Firm-Mandevilleand Schweitzer [5 7 ABSTRACT The disclosure relates to an improvedapparatus and an improved method for removing serum from the uppermostportions of a specimen tube of centrifuged blood, in which the bloodserum is disposed in a liquid pool above settled-out cellular solidmaterials. More particularly, the invention is directed to an easilyhandleable, readily mailable, collection tube closed at both ends by oneshot valve structures comprising self-sealing elastomeric elementspierced by a special one-piece hollow needle. Additionally, the lowerelastomeric element includes an annular piston-like member which isadapted to engage the inner walls of th specimen tube to pump serumtherefrom.

4 Claims, 4 Drawing Figures BLOOD SERUM COLLECTION TUBE AND METHOD CROSSREFERENCE TO RELATED APPLICATION This is a continuation, of Ser. No.148,872, filed June 1, 1971, now abondoned, which application is acontinuation-in-part of copending application Ser. No. 854,982, filedSept. 3, 1969, now US. Pat. No. 3,586,064.

BACKGROUND OF THE INVENTION In the examination of blood samples inpathological laboratories, it is often necessary or desirable to examineblood serum after it has been separated from the suspended cellularmaterial, and for this purpose it is customary to subject the specimentubes, in which the blood samples are delivered to the laboratory, tocentrifuging action to cause the settling of the cells to the bottom ofthe specimen tube. Since many laboratories process large numbers ofblood samples every day, facility of handling specimens, accuracy oflabeling of specimen, and the ease of drawing off and retaining serumspecimens are important to successful and safe operation.

Quite often, laboratory workers have experienced difficulty inefficiently removing the clear serum from centrifuged blood specimentube, without disturbing the settled out solid material. Additionally,there have been problems in maintaining with accuracy the identity ofthe source (patient) from which the serum was originally obtainedthroughout its travels from hospital to laboratory, etc.

Heretofore, the blood serum has been removed from the specimen tube,after the blood has been centrifuged to separate the serum from theclotted cells by drawing the serum off with a conventional syringe; bypouring the serum off through tilting of the specimen tube; by use ofpipettes and the like; and or by use of plungerlike apparatus of thetype disclosed in US. Pat. No. 3,355,098. The method and apparatusdisclosed in our US Pat. No. 3,586,064 represents an improvement overearlier work in this field, however, certain difficulties arose in thecreation of vacuum forces which tended to separate the lower elastomericelement from the collection tube. In addition, two separate needles wererequired to be handled.

SUMMARY OF THE PRESENT INVENTION The shortcomings of the prior artdevices have been overcome by the method and apparatus of the presentinvention, which provide a new and improved method of collecting serumand a new and improved selfsealing, serum collection tube, which tubemay be directly filled from centrifuged specimen tubes with collectedblood serum. The new serum collection tube basically comprises a hollowcylinder whose ends are closed off by novel one shot" valve structures,and whose lower end also carries a piston member. The valves themselvescomprise self-sealing elastomeric end caps pierced by portions of anelongated one-piece removable hollow needle.

For a more complete understanding of the present invention and itsattendant advantages, reference should be made to the following detaileddescription taken in conjunction with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of theapparatus of the present invention with the elongated special needle inplace and with the upper and lower one shot valves opened in preparationfor collecting a serum sample from a specimen tube;

FIG. 2 is a cross-sectional view of the apparatus of FIG. 1 during thedownward stroke of the collection tube during serum collection;

FIG. 3 is a cross-sectional view of the apparatus of the inventionduring the upward stroke of the collection tube and after serumcollection;

FIG. 4 is a front elevational view of the collection tube with both endsself-sealed by withdrawal of the needle after removal of the collectiontube from the specimen tube.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIG. 1, there isshown a conventional centrifuged specimen collection tube 10 having apool of serum 11 disposed above settled-out, clotted cellular material12. The specimen tube advantageously may be of the so-called Vacutainertype sold by Becton-Dickinson Co. for use by medical personnel inwithdrawing blood samples from patients for subsequent laboratoryanalysis. Such specimen tubes typically have inside diameters ofapproximately inch. Their lengths generally will vary depending upon thesize of the volumetric samples of blood required. Once drawn, bloodsamples are centrifuged in accordance with well known procedures toseparate within the specimen tube 10 the serum 11 and cellular matter12, as shown in FIG. 1.

The new and improved serum collection apparatus 9 of the presentinvention, includes an elongated cylindrical, clear collection tube 15which is open at its upper and lower ends. Integral annular beads orflanges 16, 17 are formed at the upper and lower ends respectively ofthe collection tube 15, as shown. Of course, the collection tubes maytake other forms, such as tubes with enlarged upper cylindricalcross-sections and reduced lower cylindrical cross-sections, in orderthat they may be compatible with special test and analyzing apparatus.

In accordance with the principles of the invention, the upper end of thecollection tube 15 is closed off by a generally cup-shaped, elastomeric,self-sealing element 18 which is mechanically connected to thecollection tube by a friction fit, threads, or by other suitable meanssuch as the illustrated resilient, split snap ring 19 (FIG. 1) to securethe element 18 of the flange 16. As an important aspect of theinvention, the upper sealing element 118 is pierced by a narrow,elongated hollow needle 20, which is of overall length greater than thelength of the tube 15. The needle 20 is made from a hardened steelsyringe needle or a clear plastic needle, which is provided withopenings or ports 5, 6 separated by a seal 7 formed by crimping or thelike. The port 5 and the upper needle opening 3 provide communicationbetween the inside of the tube 15 and the atmosphere, as will beunderstood. Advantageously, the needle 20 mounts a head or grippableportion 21 which is adapted to be grapsed by a user to facilitate thesubsequent removal of the needle 20 from the upper sealing element 18and a lower sealing element 22 after serum collection. In accordancewith the principles of the invention, the sealing element 18 and theupper portions of the needle 20 (those portions above the seal 7)comprise an upper, selectively actuatable one shot" valve.

The lower end of the collection tube, in a manner similar to the upperend, is closed off by a generally cup-shaped, elastomeric, self-sealingelement 22. A friction fit, threads, the illustrated resilient split,snap ring 23 or other suitable means mechanically fastens the element 22to the flanged, lower end of the tube, as shown. In accordance with theprinciples of the invention, the lower portion 24 (the portion below theseal 7) of the one-piece elongated, hollow needle 20 extends through thesealing element 22 to provide communication between the collection tubeand the specimen tube through the lower needle opening 4 and the port 6.

As an important aspect of the present invention, the lower cup shapedelement 22 together with the lower needle portion 24 also defines a oneshot valve. Advantageously, the outer circumference 22' of the element22 is slightly greater than the inner circumference of the tube 10 and,thereby, functions as a piston element when inserted in telescopingassociation with the specimen tube. That is to say, the cylindricalouter surfaces 22 of the elastomeric sealing element 22 areappropriately dimensioned (e.g. slightly greater than /8 inch indiameter) so that the element 22 sealingly, slidingly engages the innerwalls of the specimen tube when inserted therein, as shown in FIGS. 2and 3.

In accordance with the present invention, blood serum may be removedfrom the centrifuged specimen tube 10 and securely trapped within thecollection tube in the following manner. The lower end of the collectiontube 15 is inserted into the specimen tube, as shown in FIG. 2, andplunged downwardly therein, while the upper one shot valve is open tothe atmosphere to vent air from uppermost portions of the tube 15 as thelowermost portions fill with serum entering through port 6. Inaccordance with well known principles of pumps, the serum will be drivenby the pumplike action of the piston 22 up through the opening 4 andthrough the needle portion 24 and into the collection tube 15 throughthe port 6, without disturbing the clotted matter 12. When sufficientserum has been collected in this manner to cover the port 6, the heightof which determines the final serum level in the tube 15, the collectiontube 15 is withdrawn from the specimen tube l0, as shown in FIG. 3. Inaccordance with the principles of the invention, no air lock" orobjectionable vacuum lock interferes with withdrawal since excess serum(any serum above port 6) will drain through port 6 back into thespecimen tube until port 6 is uncovered and exposed. No vacuum will formbeneath the piston 22 since atomspheric air will be free to travelthrough the needle portion 24 and into the specimen tube. Thus, therewill be no tendency to separate the lower cap-piston element 22 from thecollection tube, as has heretofore been the case.

After withdrawal of tube 15 from tube 10, the collected serum 11 ispermanently trapped in the collection tube 15 by removing the needle bygrasping and pulling outwardly on the gripping portion 21. This closesboth the upper and lower one shot valves to provide a completely sealedcollection tube 15. The needle 20 then may be discarded and the filledtube 15 may be readily mailed to pathology laboratories for testinganalysis, etc. in a suitable mailing envelope M (shown in phantom inFIG. 1).

In accordance with a more specific aspect of the invention, the sealingelements 18, 22 are advantageously made of rubber and the collectiontube 15 is made from glass, plastic, or the like. Advantageously, thetube 15 has an etched labeling portion 26 integral therewith upon whichsuitable identifying indicia may be inscribed to ensure accuratehandling.

It should be understood that the blood serum collection method andapparatus herein illustrated and described are intended to berepresentative only, as certain changes may be made therein withoutdeparting from the clear teachings of the disclosure. For example, themethod of the invention may be practiced by dividing the needle 20 atthe seal 7 into short and long needles or by using two separate needles,a short upper needle and a long lower needle. Accordingly, referenceshould be made to the following appended claims in determining the fullscope of the invention.

We claim:

1. Apparatus for removing and trapping the upper portions of a pool ofliquid contained in a specimen tube having a predetermined innerdiameter, comprising a. a generally cylindrical tubular element of firstpredetermined length open at its upper and lower ends and having anouter diameter less than said predetermined inner diameter of thespecimen tube;

b. an elongated hollow needle of second predetermined length greaterthan said first predetermined length; said needle being open at itsextremities and having spaced ports therebetween; means sealing saidports from one another and dividing said needle into upper and lowerportions;

0. selectively actuatable upper valve means closing off said upper endof said tubular element and being adapted to provide communicationbetween interior upper portions of said tubular element and atmosphere,

d. selectively actuatable lower valve means closing off the lower end ofsaid tubular element and being adapted to communicate between said innerportions of said tubular element and the interior of said specimen tube;

e. said lower valve means comprising a puncturable,

first elastomeric sealing means secured to and closing off said lowerend of said tubular element and said lower hollow needle portionextending therethrough;

f. said upper valve means comprising a puncturable, second elastomericsealing means secured to and closing off said upper end of said tubularelement and said upper hollow needle portion extending therethrough;

g. said elastomeric material possessing sufficient resilience and saidhollow needle being sufficiently narrow whereby on the removal of saidneedle from said elastomeric material, said ends of the tubular memberwill be completely self sealed;

h. piston means including said lower end portions of said tubularelement and said lower sealing means, said piston means having an outerdiameter slightly greater than said predetermined inner diameter of saidspecimen tube, whereby said piston means is adapted to make sliding,sealing contact therewith.

2. The apparatus of claim 1, in which a. the needle mounts a grippingmeans by which the needle may be removed from said first and secondelastomeric sealing means.

3. A method of removing serum from a specimen tube comprising the stepsof a. inserting a collection tube closed off at its lower end by apiston-like element pierced by a lower hollow needle portion into thespecimen tube to drive serum upwardly therethrough and into saidcollection tube,

b. maintaining the upper inner portions of said collection tube open toatmosphere by an upper hollow needle portion while said collection tubeis driven downwardly into said serum;

c. maintaining the upper inner portions of said collection tube open toatmosphere during the upward stroke of said collection tube whileremoving said collection tube from said specimen tube;

d. maintaining the space between the lower end of the collection tubeand the interior lower portions of the specimen tube at atmosphericpressure;

e. sealing off the upper and lower ends of said collection tube byremoving said needle portions from the upper lower end thereof.

4. The method of claim 3, in which a. said upper and lower needleportions are supported and handled as a single unit, whereby said upperand lower ends may be sealed off substantially simultaneously by theremoval of said single Unlt.

1. Apparatus for removing and trapping the upper portions of a pool ofliquid contained in a specimen tube having a predetermined innerdiameter, comprising a. a generally cylindrical tubular element of firstpredetermined length open at its upper and lower ends and having anouter diameter less than said predetermined inner diameter of thespecimen tube; b. an elongated hollow needle of second predeterminedlength greater than said first predetermined length; said needle beingopen at its extremities and having spaced ports therebetween; meanssealing said ports from one another and dividing said needle into upperand lower portions; c. selectively actuatable upper valve means closingoff said upper end of said tubular element and being adapted to providecommunication between interior upper portions of said tubular elementand atmosphere, d. selectively actuatable lower valve means closing offthe lower end of said tubular element and being adapted to communicatebetween said inner portions of said tubular element and the interior ofsaid specimen tube; e. said lower valve means comprising a puncturable,first elastomeric sealing means secured to and closing off said lowerend of said tubular element and said lower hollow needle portionextending therethrough; f. said upper valve means comprising apuncturable, second elastomeric sealing means secured to and closing offsaid upper end of said tubular element and said upper hollow needleportion extending therethrough; g. said elastomeric material possessingsufficient resilience and said hollow needle being sufficiently narrowwhereby on the removal of said needle from said elastomeric material,said ends of the tubular member will be completely self sealed; h.piston means including said lower end portions of said tubular elementand said lower sealing means, said piston means having an outer diameterslightly greater than said predetermined inner diameter of said specimentube, whereby said piston means is adapted to make sliding, sealingcontact therewith.
 2. The apparatus of claim 1, in which a. the needlemounts a gripping means by which the needle may be removed from saidfirst and second elastomeric sealing means.
 3. A method of removingserum from a specimen tube comprising the steps of a. inserting acollection tube closed off at its lower end by a piston-like elementpierced by a lower hollow needle portion into the specimen tube to driveserum upwardly therethrough and into said collection tube, b.maintaining the upper inner portions of said collection tube open toatmosphere by an upper hollow needle portion while said collection tubeis driven downwardly into said serum; c. maintaining the upper innerportions of said collection tube open to atmosphere during the upwardstroke of said collection tube while removing said collection tube fromsaid specimen tube; d. maintaining the space between the lower end ofthe collection tube and the interior lower portions of the specimen tubeat atmospheric pressure; e. sealing off the upper and lower ends of saidcollection tube by removing said needle portions from the upper lowerend thereof.
 4. The method of claim 3, in which a. said upper and lowerneedle portions are supported and handled as a single unit, whereby saidupper and lower ends may be sealed off substantially simultaneously bythe removal of said single unit.